The wavelength of `K_(alpha)` line for an element of atomic number `43 is lambda`. Then the wavelength of `K_(alpha)` line for an element of atomic number `29` is

Options

A. `(43)/(29)lambda`
B. `(42)/(28)lambda`
C. `(9)/(4) lambda`
D. `(4)/(9)lambda`

Answer

C

Explanation

For `K_(alpha)` line, `lambda_(K_alpha) prop(1)/((Z-1)^(2))`
So, `" " (lambda_(2))/(lambda_(1))=((Z_(1)-1)/(Z_(2)-1))^(2)`
`rArr" " (lambda_(2))/(lambda_(1))=((43-1)/(29-1))^(2)=((42)/(28))^(2)rArrlambda_(2)=(9)/(4)lambda`